1. Field of the Invention
The invention relates to a method for reducing fuel consumption in internal combustion engines. It more particularly relates to reducing fuel consumption by adding a dimer or trimer of a polymerizable acid.
2. Discussion of the Prior Art
For several years there have been numerous efforts to reduce the amount of fuel consumed by automobile engines and the like. The search for ways to do this was given added impetus by the oil embargo. Many of the solutions have been strictly mechanical, as for example, setting the engine for a leaner burn or simply building smaller cars and smaller engines.
Other efforts have revolved around finding lubricants that reduce the overall friction in the engine, thus allowing a reduction in energy requirements thereto. A considerable amount of work has been done with mineral lubricating oils and greases, modifying them with additives to enhance their friction properties. On the other hand, new lubricants have been synthesized and compounded for use in modern engines. Among these is Mobil 1, a synthetic hydrocarbon fluid and synthetic ester blend, which is known to reduce fuel consumption by a significant amount. It is, however, the physical properties of the oil itself that provide improved lubricating (and thus improved fuel consumption) and not the additives present.
So far as is known, no effort has been made to place the acid esters of this invention in a lubricating oil. U.S. Pat. No. 3,429,817 discloses the addition to a lubricating oil of an ester made by reacting a C.sub.2 -C.sub.5 glycol with a C.sub.36 dicarboxylic acid dimer, such as the dimer of linoleic acid. It is stated to be a lubricity agent. Similarly, U.S. Pat. No. 3,390,083 discloses a mineral lubricating oil containing an antiwear agent made by reacting a C.sub.1 -C.sub.20 glycol and alcohol with a C.sub.36 dicarboxylic acid, such as the linoleic acid dimer.
Several patents disclose the use of dimer and trimer acid as an ingredient in motor fuels. U.S. Pat. No. 3,574,574 for example, teaches that by adding esters of dimer and trimers of linoleic acid (as for example the triisodecyl ester of the trimeric linoleic acid) one gets a fuel that promotes reduced intake valve and port deposits. Others that teach the presence of linoleic acid derivatives in motor fuels are U.S. Pat. Nos. 3,846,098, 2,767,144, 3,782,912, 3,844,731 and 3,925,030.